Texas moved Tuesday to drag New Mexico before the U.S. Supreme Court, charging that New Mexico is mismanaging the Rio Grande in a way that deprives Texas farms and cities of water that rightly belongs to them.

The lawsuit alleges widespread groundwater pumping between Elephant Butte Reservoir and the New Mexico-Texas border that has effectively reduced flows in the river.

As a result, New Mexico is failing to deliver water as required under the Rio Grande Compact, a 1938 deal among Texas, New Mexico and Colorado dividing up the river's sometimes scarce water.

New Mexico officials would not comment in detail on the legal issues, but in the past have argued that Texas is receiving all the Rio Grande water to which it is legally entitled.

The lawsuit represents the unraveling of relations between the states, which have been fraying for a half dozen years over how to manage growing groundwater pumping in the Rio Grande Valley downstream from Elephant Butte Reservoir in southern New Mexico.

"These illegal diversions of water in New Mexico are having an ongoing negative effect on the amount of water available for use by Texas farmers," said Pat Gordon, who represents Texas on the Rio Grande Compact Commission, in a statement issued after the suit was filed. "The city of El Paso also counts on Texas' water allocation for half of its water supply."

Texas asked the Supreme Court to force New Mexico to deliver the water it thinks its neighbor is improperly withholding.

New Mexico Attorney General Gary King issued a statement saying Texas is "trying to rustle New Mexico's water and using a lawsuit to extort an agreement that would only benefit Texas while destroying water resources for hundreds of thousands of New Mexicans."

Also commenting on the lawsuit was Gov. Susana Martinez, who said through a spokesman, "We will continue to strongly defend New Mexico's water rights. We are reviewing the Texas lawsuit and will decide how best to protect the water that is so vital to New Mexican families and businesses. We won't cede a single inch of New Mexico water to Texas."

The amount of water being used unlawfully in New Mexico, rather than being delivered to Texas, is enough to irrigate thousands of acres of farmland, Texas charges in the suit. The lawsuit does not give a specific amount.

The suit also names Colorado, as a third party in the compact, as a defendant. But the brief makes clear that Texas' beef is entirely with New Mexico's water management.

The dispute over lower Rio Grande management has already led to litigation in both Texas and New Mexico courts over the past six years. But in taking the case to the Supreme Court, Texas has elevated the dispute to a new level. That court, Texas argued in its filing, is the only one with the jurisdiction to settle a dispute between the two states.

Water managers have been expecting the suit, after the inability of state representatives to settle a growing conflict over how to account for and distribute water flowing south from Elephant Butte Reservoir into southern New Mexico and Texas. It is the latest in a series of conflicts between New Mexico and Texas over the river that stretches back, in one form or another, for more than a century.

In New Mexico, water released from Elephant Butte and groundwater in the surrounding Rio Grande Valley provides water for farms in the Elephant Butte Irrigation District and municipal users in the Las Cruces area.

Water flowing downstream is then used by Texas farmers and provides half of the drinking water supply for El Paso. Farmers in Mexico also get a share.

Questions about groundwater have long been at the center of lower Rio Grande water management discussions, in part because of widespread use of groundwater pumps by farmers to supplement supplies during years when the Rio Grande is dry.

Last year, New Mexico State Engineer Scott Verhines concluded that groundwater use had exploded in recent years as drought sapped flows on the Rio Grande.

The current legal battle began in 2007, when El Paso farmers went to court in Texas arguing that New Mexicans were pumping too much groundwater. To try to solve that problem and head off an escalation of that litigation into a full-fledged interstate battle before the U.S. Supreme Court, the Texas and New Mexico irrigation districts, along with the federal government, worked out a new deal in 2008 that effectively gave Texas more Rio Grande river water as a payback for the effect of groundwater pumping.

But in August 2011, the state of New Mexico filed suit against the U.S. Bureau of Reclamation, which runs Elephant Butte Dam, in federal court, charging that the agreement gave away too much New Mexico water to Texas. Verhines, in a statement Tuesday evening, called the Texas lawsuit an attempt to divert attention away from issues raised in that litigation.

Combined with a parallel legal battle currently under way in New Mexico state court, Texas officials said they were left with no recourse but to take the whole thing before the U.S. Supreme Court.